Acute trauma alters morphine clearance

Area of Science:

• Pharmacology
• Trauma Medicine
• Drug Metabolism

Background:

• Trauma impacts liver perfusion and acute phase proteins, potentially altering drug metabolism.
• Limited research exists on drug disposition in acute trauma patients.
• Morphine pharmacokinetics are not well-characterized in the context of severe injury.

Purpose of the Study:

• To determine the pharmacokinetics of morphine, an intermediate extraction drug, in patients experiencing acute trauma.
• To investigate the influence of trauma-induced physiological changes on drug disposition.
• To provide data for optimizing morphine dosing in trauma care.

Main Methods:

• Studied nine trauma patients with an Injury Severity Score (ISS) >= 16 within 48 hours of injury.
• Administered a 5 mg intravenous dose of morphine.
• Collected serial blood and urine samples to calculate pharmacokinetic parameters and measured alpha-acid glycoprotein (AAG) levels.

Main Results:

• Observed decreased total morphine clearance (CL) and volume of distribution (Vss) compared to literature values.
• Found increased area under the curve (AUC) and terminal half-life (T 1/2 alpha).
• Noted elevated AAG levels and an increased elimination half-life, suggesting increased morphine binding.

Conclusions:

• Increased AAG levels post-trauma likely contribute to the reduced Vss of morphine.
• Decreased clearance and prolonged half-life may result from increased protein binding, reduced liver blood flow, and impaired hepatocellular function.
• Understanding these pharmacokinetic alterations is vital to prevent drug accumulation and ensure appropriate morphine dosing in trauma patients.